Micro-cutting systems for forming cuts in products

ABSTRACT

Micro-cutting machines for forming cuts in catheters, guidewires, and similar products, are disclosed, including a micro-cutting machine that can directly control the dimensions of the resultant beams being cut into products, and that can capture images of each cut for feedback control and accuracy verification.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/633,727, filed Dec. 8, 2009, which claims the benefit ofU.S. Provisional Patent Application Ser. No. 61/120,703, filed 8 Dec.2008, and U.S. Provisional Patent Application Ser. No. 61/166,480, filed3 Apr. 2009, each of which is herein incorporated by reference in itentirety.

BRIEF DESCRIPTION OF THE INVENTION

Micro-cutting machines for forming cuts in catheters, guidewires, andsimilar products, are disclosed, including a dual blade micro-cuttingmachine that can directly control the dimensions of the resultant beamsbeing cut into the products, that can capture images of each cut forfeedback control and accuracy verification, and that generally can cutany material (such as plastic) independent of the conductivity of thematerial.

BACKGROUND OF THE INVENTION

The medical field utilizes highly flexible and torquable catheters andguidewires to perform delicate procedures deep inside the human body.Endovascular procedures typically start at the groin where a catheterand guidewire are inserted into the femoral artery and navigated up tothe heart, brain, or other anatomy as required. Once in place, theguidewire is removed so the catheter can be used for the delivery ofdrugs, stents, embolic devices to treat a variety of conditions, orother devices or agents. The catheter may be a balloon catheter used fortherapy directly, either by itself or with a balloon expandable stentpre-loaded on it. A radiopaque dye is often injected into the catheterso that the vessels can be viewed intraprocedurally or in the case of adiagnostic procedure, the dye may be the primary or only agent deliveredthrough the catheter.

Intravascular procedures, by definition, work in and with delicateanatomy, namely the vessels themselves, which are often also compromisedby disease. Damage to the vessels is particularly critical to avoid. Ifblood in the vessels is allowed to “leak,” direct damage can be causedto any tissue outside of the normal capillary approach contacted by theblood, and/or may result in a deadly problem of exsanguination or “bleedout”. When treating an aneurysm, the control of the catheter tip isespecially important. An aneurysm is a very fragile ballooned vesselwall which can easily be punctured if the guidewire or catheter is notprecisely controlled.

The guidewires and catheters produced with current technology machines(as described in published patents) have limited functionality. Anexample of such a micro-cutting machine is disclosed in U.S. Pat. No.6,014,919, issued to Jacobsen et al. on 18 Jan. 2000. Due to the singleblade design and other aspects of these existing machines, the machineslack the precision necessary to control small (sub 0.002″) features on areliable basis. They also lack the ability to precisely control andverify larger features, which could affect the safety and/or performanceof these devices. These machines are also only capable of working withelectrically conductive stock material because the machines rely on theelectrical conductivity of the stock material to determine the positionof the stock relative to the cutting blade. Each cut made by the bladeinto the stock is based on the location of the electromagneticallysensed surface of the stock and the pre-programmed depth of the desiredcut. Once a cut is made, the stock piece is rotated 180 degrees, thesurface is sensed again, and another pre-programmed cut is made to adesired depth. As the cutting machine is incapable of determining theprecise diameter (at the location of the cut) of the stock materialbeing cut, each cut is made according to a preprogrammed depthregardless of that diameter. This is a problem because stock material isnot always of a uniform shape and diameter—there are often imperfectionsalong the length of stock that can affect both the roundness of thestock material and the diameter of the stock material at any particularlocation.

When the stock material is cut in the manner practiced by currentcutting machines, a small beam of remaining material, of varyingthickness, is formed by the sequential, opposing cuts. This beam isreferred to as a resultant beam. If the diameter of the stock is thickerthan anticipated at the location of the cuts, then the resultant beamwill be thicker and therefore less flexible than desired. If thediameter of the stock is thinner than anticipated at the location of thecuts, then the resultant beam will be thinner and therefore weaker thandesired. Thus, the critical dimension that governs both strength(safety) and flexibility (performance) is the width of the resultantbeam, which in current micro-cutting machines is not controlled directlyand is instead the result of two imprecise measurements—the measure ofthe relative distance between the blade and the stock material for thefirst cut and the measure of the relative distance between the blade andthe stock material for the second cut. Any imperfection in the surfaceof the stock material, or inconsistency in the diameter of suchmaterial, is directly translated to the resultant beam. This isproblematic in terms of both safety and performance of the finalproduct, whether it is a guidewire, catheter or other device. It isespecially critical when forming small dimension resultant beamsrelative to a larger dimension stock material, as an acceptabletolerance relative to the larger diameter of the stock material may beunacceptably large compared to the smaller dimension of the resultantbeam. Existing technology is also unable to cut any kind ofnon-conductive material, such as plastic. The existing cutting machinesrely upon electrical conductivity to sense the surface of the materialbeing cut and then make the cuts.

It would therefore be advantageous to create a micro-cutting machine formachining catheters, guidewires and other devices that utilizes twoblades to cut both sides simultaneously, that is able to directlycontrol the width of resultant beams, and that is capable ofmicro-cutting non-conductive material, such as plastic. Such a machinewould be faster, more predictable, and more versatile than currentmicro-cutting machines.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 illustrates a general overview of a micro-cutting machine in anembodiment;

FIG. 2A illustrates a partially cut-away, plan view of a cuttingassembly of the micro-cutting machine of FIG. 1 in an embodiment;

FIG. 2B illustrates a cross-sectional view of a piece of cylindricalstock material resting within a feed trough of the cutting assembly ofFIG. 2A in an embodiment;

FIG. 3 illustrates a desktop image generated by the imaging system andCPU of FIG. 1 depicting the stock material once it has been cut by thecutting assembly;

FIG. 4 illustrates the imaging system of the cutting assembly of FIG. 1;

FIGS. 5A, 5B and 5C illustrate different views of a product cut inaccordance with an embodiment; and

FIGS. 6A and 6B illustrate cross-sectional views of pieces ofcylindrical stock material cut to form different products in accordancewith an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The herein disclosed micro-cutting machine utilizes a pair ofmicro-cutting blades or other cutting members to precisely cut intoopposing sides of a cylindrical stock material. By cutting both sidessimultaneously while tightly controlling the distance between the bladesor cutting members, the disclosed micro-cutting machine is capable ofproducing high performance catheters, guidewires and related productsfor interventional medical procedures, as well as other devices for avariety of additional uses. While an embodiment has been designedprimarily for cutting stock material into flexible and torquable medicalguidewires and catheters, the disclosed micro-cutting machine cancertainly be used for other applications, and may be appropriate formaking precise micro-cuts into a wide variety of cylindrical materialsor perhaps even other extruded stock materials which may havenon-circular cross-sectional shapes. The micro-cutting machine willmostly be described in regard to cutting guidewires and catheters, butthose skilled in the art will recognize the broader applicability of theembodiment.

FIG. 1 illustrates a general layout of the micro-cutting machine inaccordance with an embodiment. Micro-cutting machine 101 includescutting assembly 140, which generally has at least a pair of blades orcutting members and two or more stock material controllers, includingfeed and rotate motors, for precisely advancing and controlling theangle of the cylindrical stock material as it is cut and then preparingfor a next cut. Cutting assembly 140 will be explained in much moredetail below. Communicatively connected to cutting assembly 140 areelectronic controllers 110 (which may be one or more electroniccontrollers, which are referred to as an electronic controller unit) forproviding precise control signals to the cutting assembly 140 to controlthe position and speed of the blades and the position and angle of thestock material. The electronic controllers can also control the lightsand a camera (an imaging system) for imaging the stock material beforeand after cuts and collecting data generated by the imaging system. Acentral processing unit 130 (such as a personal computer that includes adisplay, input and output systems, a storage system, etc., or some othertype of CPU) receives user input, controls the electronic controllers110 and the cutting assembly 140, and processes data generated by theimaging system to adjust the relative gap distance between the twoblades. Alternatively, the CPU 130 could communicate directly with theimaging system and by-pass the electronic controllers 110. A powersupply 120 supplies power to at least the cutting assembly 140, andpossibly other components of the micro-cutting machine 101.

FIG. 2A illustrates a plan view of an embodiment of cutting assembly140, which is mounted on a stationary frame assembly 200. The stockmaterial 202 is fed into the cutting assembly 140 by the feed motorassembly 204, which can hold the stock material in a fixed positionrelative to the X-axis, the direction parallel to the spindle 206, andwhich can move the stock material along the X-axis by very small,controlled increments, so as to appropriately feed the stock material202 into the cutting assembly 140, as further discussed below. The feedmotor assembly 204 may comprise two feed motors (not separately shown),one for gripping the stock material 202 while it is being cut, asfurther described below, and one for moving the stock material 202 alongthe X-axis when the stock material 202 has been released by the firstfeed motor.

The stock material 202 shown in FIG. 2A is not illustrated as its actualsize. The outer diameter of the stock material 202 can be 0.030 inchesor less, or about 3 French on the French catheter scale, where a Frenchis equal to three times the outer diameter of the stock material 202measured in millimeters. Converting to inches, 3 French is equal to0.039 inches, 4 French is equal to 0.053 inches, 5 French is equal to0.066 inches, 6 French is equal to 0.079 inches, etc. Accordingly, basedon the relative size of the cutting assembly shown in FIG. 2A, even alength of 6 French stock material 202 would be so small as to be almostimpossible to see clearly, so the stock material 202 illustrated in FIG.2A is much larger than its actual size for purposes of this illustrationonly.

The feed motor assembly 204 is mounted on a spindle 206 that issupported within the bearings of a bracket 208 mounted to the stationaryframe assembly 200. A pulley 210 mounted to the spindle 206 is driven bya belt (not shown) that is, in turn, connected to another pulley (notshown) below the pulley 210, which is connected to a rotational motor(not shown) mounted within the stationary frame assembly 200. Therotational motor is a stepper motor, or the like, that is capable ofextremely precise computer controlled movement. Based on programmingprovided through the electronic controllers 110 and the CPU 130 (such asthrough a user interface that allows a user to change certain parametersof operation of the electronic controllers 110 and therefore variouscomponents of the cutting assembly 140), the rotational motor can beprogrammed to cause the pulley 210 to rotate a specified number ofdegrees, so as to rotate the spindle 206 and feed motor 204 by the samespecified number of degrees. Hence, the entire feed motor assembly 204rotates, along with any gripped stock material 202 when the pulley 210and spindle 206 are rotated by the rotational motor. Alternativeembodiments could include different arrangements of the feed motorassembly 204 and the rotational motor, such as a feed motor assemblythat only moves the stock material 202 along the X-axis and a rotationalmotor that grips and turns the stock material 202 when it is not beingfed along the X-axis.

In order to better illustrate the relationship between the variouscomponents of the cutting assembly 140, the stock material 202 is shownexiting the feed motor assembly 204 supported by an elongated feedtrough 212, which extends from the feed motor assembly 204 to one sideof the cutting area (where the stock material 202 is cut by the blades214, as further described below), and then extends from the other sideof the cutting area to an output area 216. In reality, the length of thefeed trough 212 between the feed motor assembly 204 and the cutting areawould be relatively short. This enables the feed motor assembly 204 tobe much closer to the cutting area, such that the stock material 202would be cut almost immediately upon exiting the feed motor assembly204. Keeping the length of the stock material 202 short between the feedmotor assembly 204 and the cutting area helps to better control thestock material 202 while it is being cut, i.e., preventing the stockmaterial 202 from moving along the Y-axis, the direction perpendicularto the spindle 206, or rotating while the stock material 202 is beingcut.

It should also be noted that most of the stock material 202 is likely tobe substantially rounded in shape, although other shapes could also beused. The stock material 202 has both width and height, giving it aY-axis and Z-axis position, where the Z-axis is vertical to a planeincluding the X-axis and Y-axis. The feed trough 212 is intended topassively guide the stock material 202 as it is moved along the x-axis,which it could do in many different ways, such as through theutilization of precisely located guide posts or elongated members or aguide path that maintains the stock material 202 in a desired positionrelative to the Y-axis and Z-axis. The guide path of the feed trough 212for rounded stock material 202 is preferably V-shaped, as illustrated bythe cross section shown in FIG. 2B, wherein the stock material 202 liesin the bottom of the point formed by the V-shaped guide path within thefeed trough 212.

As noted above, the cutting area is defined by a small gap between thetwo sections (prior to and after the cutting area) of the feed trough212 where a pair of opposing blades 214 cut the stock material 202. Inan embodiment of the application, the two blades 214 can be eithersemiconductor dicing blades or standard “tooth” type blades formed of acarbide material, such as tungsten carbide, to improve wear resistance.The submicron grain size of tungsten carbide and similar compositesworks well because they are less brittle, extremely hard, and canmaintain their sharpness even at very small blade thicknesses. In anembodiment, additional different types of cutting instruments andsystems could be utilized in place of the blades 214, such as water jetcutting systems, flame or oxyfuel cutting systems, plasma (arc) cuttingsystem, electric discharge machining (EDM), etc., although not all ofthese systems are appropriate for use when cutting non-metal stockmaterial or even certain types of metal stock materials, such as softermetals and less conductive metals. Given the variable operation of suchadditional types of cutting systems, it may also be necessary and/ordesirable to change the orientation of the cutting assembly 140 and/orthe stock materials 202 so instead of bringing the cutting point of theblade or system down along the Z-axis, the cutting point may be moved inthe X-axis, or the cutting point may be held stationary while the stockmaterials is moved relative to the cutting point. All such alternativecutting systems are anticipated herein. Hence, when reference is madeherein to a “dual blade” system, it is to be understood that any type ofalternative cutting member or cutting system could also be used,depending on the application involved.

An embodiment for cutting plastic utilizes a tooth type blade withapproximately 56 teeth. When cutting PEEK (polyetheretherketone) andother plastics with this blade type, a blade thickness of approximately0.006 and 0.008 inches works well. When cutting nitinol, stainless steeland other hard metal and composite materials, a diamond semiconductordicing blade with a thickness of approximately 0.002 inches works well.Given such thickness, the size of the open cutting area between the twosections of feed trough 212 represented in FIG. 2A is not to scale andis exaggerated in size in order to more clearly illustrate the openingof the cutting area. Of course, the blades 214 shown in FIG. 2A appearto be much larger in diameter than they really are as well, especiallysince, in most cases, they are only required to make very shallow cutsin the stock material 202. Since the stock material 202 could be formedof any type of material having any size diameter, such larger stockmaterial would obviously need to be cut with thicker blades havinglarger diameters than those used to cut guidewires and catheters.

As will be further noted below, the embodiment does not require thestock material 202 to be of a metallic composition so its location canbe electromagnetically sensed by the blades 214 before a cut can bemade. The embodiment can be used to cut any type of material, whethermetallic or non-metallic, such as PEEK, a semi-crystalline, hightemperature thermoplastic that is ideal for use in catheters due itshigh modulus of elasticity resulting in torqueability and the ability tohold a shape. Although the general belief in the art has been that lowercutting speeds were necessary, especially when cutting PEEK, to reducespur generation in the area of each cut, this was found not to be thecase; much higher rotational speeds of the blades 214 worked well toreduce spur generation and provide exception accuracy. The embodimentalso cuts other materials, including stainless steel and metalliccomposites at very high speeds with no burrs and with exceptionalaccuracy.

The blades 214 are located within a blade enclosure 218 (shown withoutits top in FIG. 2A so the interior can be viewed) through which air canbe pumped to cool the blades 214 and the stock material 202, and throughwhich debris cut from the stock material 202 can be removed. The hoses220 of the air handling system can be used for pumping air and/orvacuuming air from the blade enclosure 218. The blades 214 can also bewater cooled, as is known in the art.

In order to drive the blades 214 directly at higher speeds withoutrequiring more expensive motors and added additional complications, eachof the blades 214 is attached to a spindle 222, that is orientedparallel to the X-axis. Each of the spindles 222 is driven by a belt 224that is rotated by a pulley attached to the spindle motor 226. Thespindle motor 226 is program controlled through the electroniccontrollers 110 and the CPU 130. The blades 214 are driven indirectly inthis manner so as to achieve greater rotational speeds than would bepossible or practical with a direct drive arrangement. For example, thespindle motor 226 is capable of running at approximately 4,000revolutions per minute (rpm) over an extended period of time withoutstressing the spindle motor 226 or any of the bearings supporting thepulley. The aspect ratio between the pulley and the spindle 222 isapproximately 6:1, so the slower rotating spindle motor 226 is capableof rotating the spindle at approximately 24,000 rpm, the desired speedfor cutting PEEK and other materials. A direct drive motor capable ofoperating at 24,000 rpm would be significantly more expensive, requiredifferent bearing assemblies, and likely have a significantly higherfailure rate.

The combination of the blade 214, the spindle 222, the spindle motor 226and pulley, and the belt 224 is referred to herein as a “cuttingassembly”, but the same term would apply if a different cutting systemwithout blades was being used as well. Each cutting assembly is attachedto a blade stepper motor 228 that controls the Y-axis location of eachblade 214. The stepper motors 228 are mounted on a movable frameassembly 230, as further described below. Each of the stepper motors 228are program controlled through the electronic controllers 110 and theCPU 130, or can be manually adjusted through the control knobs 232.

To cut a piece of stock material 202 so as to leave a resultant beam, asfurther described below, of a specified dimension, each of the steppermotors 228 are adjusted to a predetermined location such that the blades214 are close but not touching, and a cut is made in the uncut stockmaterial 202 with both blades at the same time. The manner in which bothblades cut the stock material 202 simultaneously is further describedbelow. Once the cuts are made, the resultant beam is measured todetermine if it is of the desired dimension. The stepper motors 228 arethen adjusted along the Y-axis to move the cutting assemblies inwardtoward each other or outward away from each other, and another cut ismade to the uncut stock material 202. This process is continued untilthe desired resultant beam dimension is achieved, at which point aseries of cuts in the uncut stock material 202 is carried out.

By mounting the cutting assemblies on the stepper motors 228, it ispossible to precisely control the Y-axis location of each blade 214 andto accommodate a larger variety of different stock materials 202, suchas raw wire, tubing, and other shapes and sizes of cylindrical stockmaterials 202. For example, if a wide diameter catheter is to be cutfrom a relatively wide diameter piece of tubing, the stepper motors 228can move the cutting assemblies apart to accommodate the larger thannormal stock material. In another example, it may be that a user wishesto micro-cut a piece of metal wire for a guidewire having 0.002 inchresultant beams at one end and 0.004 inch resultant beams at theopposite end, with a gradual transition between the two beam widths. Inthis example, the stepper motors 228 can be precisely controlled byelectronic controllers 110 and processor 130 to position the blades 214to make cuts resulting in the desired resultant beam width, whether thatbe 0.002 inches, 0.0025 inches, 0.003 inches, 0.004 inches, etc. Thus,almost any desired dimension can be machined at any specified location.

Both of the cutting assemblies and the stepper motors 228 are in turnmounted on the movable frame assembly 230, which is moved up and downalong the Z-axis by a Z-axis motor (not shown) located within themovable frame assembly 230 and mounted on a non-visible portion of thestationary frame assembly 200. By mounting the cutting assemblies andstepper motors 228 on the movable frame assembly 230, it is possible toprecisely control the Z-axis position of both blades 214 at the sametime. The blade enclosure 218 can be designed to be mounted to themovable frame assembly 230, such that the blade enclosure 218 movesalong with the blades 214, or blade enclosure 218 could include twoslots within which the spindles 222 could move up and down apart fromthe blade enclosure 218. So as to better seal the interior of the bladeenclosure, it is preferable to have the blade enclosure 218 move withthe blades 214.

Also shown in FIG. 2A (by dotted lines so that underlying components arevisible) is the imaging system of the embodiment, which primarilycomprises a digital camera 234 mounted within an upper cowl 236 andupper and lower lights, not shown. The upper cowl 236 is mounted to thestationary frame assembly 200 so that the camera 234 does not move alongthe Z-axis as the blades 214 move. The camera 234 is positioned directlyover the cutting area and is focused on a portion of the stock material202 as it is being cut and just after it has been cut, as furtherillustrated in FIGS. 3 and 4.

The camera 234 could be any of a number of commercially availablehigh-speed digital video cameras as long as it is capable of capturinghigh quality pixilated video image data. In an embodiment, the camera isa model AM-413T digital microscope camera, manufactured by SunriseDinoof New Hyde Park, N.Y. The more interesting aspects of the imagingsystem are the manner in which the stock material 202 is backlit andilluminated in order to increase contrast around the edges of the cutstock material 202 and how the digital image processing is capable ofprecisely measuring both cuts and the resultant beams.

FIG. 3 is an illustration of a desktop image 300 generated on thedisplay of the CPU 130. The desktop image 300 includes an imaging window302 and a control window 304. The imaging window 302 displays digitalvideo images of the stock material 202 as it is being cut and as it isbeing measured by the imaging system. The area 306 shows the stockmaterial 202 just after it has been cut by the blades 214 and the blades214 have moved beyond the focused view of the camera 234. The stockmaterial 202 being cut in the example illustrated in FIG. 3 is a tubeused to make a catheter that is being rotated ninety degrees)(90.degree.) after each cut. Once a cut has been made, holes 308 areformed in the walls of the stock material 202 that become visible as thestock material 202 is turned in order to make the next cut. As the stockmaterial 202 advances along the X-axis of the cutting assembly, thestock material 202 passes in front of a backlight, illustrated by thecircle 310.

Referring briefly now to FIG. 4, the camera 234 of the imaging system400 is placed directly over the top of stock material 202, so that itmay image and measure the stock material 202 and the resultant beam 314formed by the two cuts. As discussed above, feed trough 212 leaves a gapthrough which the blades 214 can pass. The backlight 410 is an opticalfiber, or a bundle of several optical fibers, through which red LEDlight 420 is provided by the imaging system. The optical fiber providingthe backlight 410 is passed through a separately drilled hole (notshown) that enables the backlight 410 to shine around the stock material202 and be visible to the camera 234. The backlight 410 is held in placebelow the cutting area by an anvil that is affixed to the stationaryframe assembly 200 and is positioned to illuminate the stock material202 just after it has been cut, although the stock material 202 can alsobe seen in imaging window 302 just as it is being cut. Camera 234 iscommunicatively coupled to processor 130 (not shown in FIG. 4) in orderto provide feedback while the stock material 202 is being cut, and inorder to store one or more images of one or more resultant beams 314.

A set of one or more green and blue LEDs 430 can be positioned above thestock material 202 and around the camera 234 to provide additionallighting 440 for a user to see the top side of the stock material formanual inspection purposes. The combination of a red backlight 410 andthe green and blue LEDs 430 was selected because the camera 234 providesthree color image channels of image data (red, green and blue) and theseparately colored lighting enables the image data to be easilyseparated. The CPU 130 (and the software it operates) receiving theimage data uses the red image channel for edge detection because itprovides a high-contrast back lit image of the cut with no front sidereflections that would confuse the measurement software being utilizedby the CPU 130 to measure each cut. The green and blue image datacreated by the green and blue LEDs 430 and the camera 234 aretransmitted through the green image channel and the blue image channel,respectively.

A purpose of the imaging system 400 is to monitor the exact location andsize of cuts formed in the stock material 202. This information, meaningthe image of a cut and resultant measurements, can be used in a numberof different ways. For example, the images can be used to validate theaccuracy and repeatability of the micro-cutting machine at or near intime to when the stock material 202 is being cut. If the images arebeing analyzed on the fly—while in the process of making the many cutsnecessary to transform a piece of stock material 202 into a catheter orguidewire—the imaging system 400 can be used to stop production on thatpiece if a cut goes awry or the stock material 202 is out of tolerance.

Returning now to FIG. 3, although the camera 234 could theoreticallycapture an image of every single cut made to the stock material 202,doing so would generate an excessive amount of data that could not becompetently reviewed at a reasonable cost by human operators. Instead,so as to provide adequate quality control, images are captured andrecorded on a periodic or random (randomized test sampling protocol)basis, as further described below. While an image of the stock material202 is being captured, as illustrated in FIG. 3, two visual overlays 312are applied by the imaging system to the image data within the back litarea 310 to determine the length of each cut and the resultant beam 314,which is referred to as the “web” in FIG. 3. The overlays 312 measureacross the stock material 202 at two or more different points, includingat least the width or thickness of the stock material 202 and the widthof the web or resultant beam 308.

The measurements taken by the overlays 312 are then analyzed by the CPU130 and utilized to determine the length of the left cut, the right cutand the resultant beam or web 314. For example, by pre-determining thenumber of pixels per unit of measurement in the image being captured,and then counting the number of pixels displayed in the image data forthe length of an object to be measured (using real-time image processingsoftware operated by the CPU 130), it is possible to determine accuratemeasurements from the image data alone, without having to make use ofmechanical measuring means. For example, if it is known that a piece ofstock material 202 to be cut should have a width of 0.039 inches and theimage data has a pixilation of 500 pixels per 0.05 inches, thenapproximately 390 pixels correspond to the width of the stock material202. If a cut is then made in the stock material 202 from both sidesleaving the resultant beam 314, and that resultant beam 314 is measuredat 359 pixels, then the resultant beam 314 has a width of 0.0359 inches.Similar measurements can be made of each cut in the stock material 202and these real-time measurements can then be displayed at 316 so theprogress of the cutting operation can be monitored by an operator or theCPU 130.

When the width of the stock material 202 at the point of a cut isthicker or thinner than expected, the resultant beam 314 will still bewithin an acceptable range of its normal size because the position ofthe blades 214 relative to the stock material 202 is largely based onthe centered position of the stock material 202, versus the knowntechnique of basing each cut on the relative difference of the separateblades to the side of the stock material each blade is responsible forcutting. Hence, when thicker stock material 202 is cut, more stockmaterial is cut away and when thinner stock material 202 is cut, lessstock material is cut away, but in each case leaving a resultant beam ofthe desired size, versus generating thicker or thinner desired resultantbeams, as is common in the art.

The control window 304 displays each measurement in a log section 318 ofthe control window that can be scrolled. As illustrated in FIG. 3, theCPU 130 has been programmed to instruct the imaging system to capture animage and measure the left cut, the right cut and the web on a periodicbasis. For example, the first cut shown was grind 995 that resulted in aleft cut (CUTL) of 0.0018 inches, a right cut (CUTR) of 0.0013 inches,and resulted in a web of 0.0359 inches, as noted above. The measurementsand image file for grind 995 is then stored in a data file labeledA.sub.—133.JPG. The grinds being recorded do not necessarily correspondto the same number of cuts that have been made, as more or less cuts maybe made than are imaged, measured and recorded. Hence the stepsillustrated as part of the log section 318 may correspond to a separateprogrammed process that keeps track of the number of cuts that have beenmade.

The control window 304 also includes selectable buttons 320 that allowan operator to stop or pause a job or start and stop the cuttingprocess. The operator also has the option of assigning a title to eachcutting job and to store the data associated with that cutting job in aparticular folder on the CPU 130.

As previously noted, the CPU 130 provides programmed control of theelectronic controllers 110, the rotational motor and the feed motorassembly 204 to control the movement of the feed stock 202 into thecutting assembly 140 along the X-axis. Once the stock material 202 hasbeen fed into the cutting assembly and gripped by the feed motorassembly 204, the CPU 130 would instruct the rotational motor either toleave the stock material 202 at its current orientation or to rotate itby some degree specified by the CPU 130. Once the stock material 202 hasbeen cut, the feed motor assembly 204 would advance the stock material202 by some specified amount along the X-axis to position it for thenext cut and grip the stock material 202. The rotational motor wouldthen rotate the feed motor assembly 204 and the stock material 202 wouldbe cut again. This process would then be repeated until all of the stockmaterial 202 has been cut as desired.

By rotating the stock material 202 between each cut, the cuttingassembly 140 can generate a cut stock material 202 with resultant beams314 that are not all aligned in the same orientation along the length ofthe micro-machined product. For example, the stock material 202 could beturned ninety degrees from its angle at the time of the last cut, ormany variations thereof, such as turned five or more degrees short ofninety degrees (i.e., 85 degrees) from the angle of the last cut, oreven cut at random angles relative to the angle of the last cut.

An additional feature of the embodiment is the ability to measure thestock material 202 prior to being cut and using the resultantmeasurement to guide the depth of cuts. If stock material 202 wasassumed to be 0.039 inches in diameter and it was desired to create aresultant beam 314 having a thickness of about 0.008 inches, then eachcut would need to be 0.0155 inches deep. If the imaging systemdetermined that the stock material 202 was only 0.032 inches in diameterinstead of 0.039 inches, then the cutting machine would know that itneeded to reduce the depth of each cut to 0.012 inches so as to leavethe desired resultant beam 314 of 0.008 inches. However, as noted above,this is not necessary with respect to the embodiment where two blades214 cut down from opposite sides of the stock material 202 because oncethe relative gap between the blades 214 has been established (that isrelative to the cutting points of the two blades 214 or other cuttingmembers), the gap dictates precisely the resultant beam 314 regardlessof the outside diameter of the stock material 202. While the amount ofmaterial, or “depth of cut” is indeed different, there is no differencein the resultant beam 314 width.

In certain cases, however, it may be desirable to operate the blades 214in an “offset cut” mode, wherein the blades 214 are not aligned in thesame plane and deeper cuts are made. In this case, the cuts appear asindependent cuts from each side (although cut simultaneously). The depthwould then be important as each resultant beam, and the flexibility andstability of this type of structure, would be determined by the distancefrom the end of the cut to the opposing side of the tube. Although thistype of structure could be made using the embodiment, it may not beterribly practical since it would require the cutting machine to imageand measure the stock material 202 before each cut was made and toadjust the stepper motors 228 on the fly in the event it was determinedthat the stock material 202 was of the wrong diameter in order to changethe depth by which the cuts are made.

Accordingly, the embodiment presently relies upon a quality controltechnique that measures only some of the cuts after they have been madeinstead of every cut. This enables the system to monitor the quality ofthe stock material 202 and other aspects of the system, but does notnecessitate changing how the system is operating from cut to cut. Forexample, in the event stock material 202 was out of specification, it isnot likely that its diameter would only vary at a single isolated point.Rather, if stock material 202 was out of specification at one point, itwould likely be out of specification along of a length of the materialor be out of specification at multiple individual points, one or more ofwhich would be detected through the quality control technique. Largevariations in the diameter of the stock material 202 may make the stockmaterial undesirable for certain applications, so if this wasdetermined, the cutting assembly 140 could be stopped and the productdiscarded once detected.

As stated, a main purpose of the micro-cutting machine is to make pairsof cuts (but not necessarily opposing) on cylindrical stock material toform flexible and torquable products, such as guidewires, catheters andother similar types of devices, all referred to herein as “products”.While it is known in the art to create a flexible and torquableguidewire and catheter by making a single cut with a blade into a sideof a cylindrical piece of stock material (metal wire and/or tubing), andthen rotating the material and making an opposing cut on the oppositeside of the stock material with the same blade. When this process isperformed along all or part of the length of the stock material, thediameter of the stock material is reduced in numerous places, whichincreases the flexibility of the resulting product, but since theproduct retains the same overall outside diameter, the resulting productis able to retain much of its torquability. While the stock material cutin this fashion is usually cylindrical, since the cuts are made fromopposing sides or nearly opposing sides toward the middle, it is helpfulto think of the stock material as having a first side and a second side,even though in reality the stock material is substantially round and hasonly a single side.

FIG. 5A illustrates the resulting beams that are generated by circularblades that cut from a first side and then a second side, a resultingbeam that can also be generated through utilization of the embodiment.FIGS. 5B and 5C illustrate resulting beams that can only be generatedthrough utilization of the embodiment. A cross-sectional view of solidstock material 202 is shown in FIGS. 5A, 5B and 5C. Based on existingtechnology, when the solid stock material 202 has been cut on the firstand second sides (either all at once, as is presently disclosed, or onthe first side and then on the second side, as is known in the art), aresultant beam 510 would remain. This type of resultant beam 510 isknown in the art as a radius cut beam because it tapers from thecircumference to the center point. Existing technology cuts the solidstock material 202 by advancing toward the solid stock material 202along the Y-axis described above. As a result, the circular blade cutsthe stock material 202 further in the central area than it can on theouter areas, always resulting in the radius cut beam 510.

Although a radius cut beam 510 is appropriate for some uses, it is notideal from a torquability and safety perspective. The reduced thicknessof the central area of the radius cut beam 510 enables stress to buildup in that area as the product is twisted, which can result in breakageof the product. Given that products are often used in intravascularprocedures, any breakage is highly undesirable. Likewise, if there isany irregularity in the diameter of the product, which irregularitycannot be sensed by the cutting machine, the cutting machine will make acut in the product based on its programming alone. Hence, using theexample provided above, if a guidewire was 0.039 inches in diameter andit was desired to create a resultant beam having a thickness of about0.008 inches at the central area, then each cut would need to be 0.0155inches deep. If the guidewire, however was only 0.032 inches in diameterand the cutting machine used electromagnetic sensing, instead ofreal-time imaging, then each side would still be cut by 0.0155 inches,leaving a resultant beam of 0.001 inches, which would also likely resultin breakage when inserted into a simple curve.

The presently disclosed cutting machine, however, operates by moving thedual blades 214 along both the Y-axis and the Z-axis and is capable ofcreating a variety of differently shaped resultant beams, including theradius cut beam of FIG. 5A, as well as the straight cut beam of FIG. 5Band the convex cut beam of FIG. 5C. To create the straight cut beam, thecutting assemblies are moved above the stock material 202 along theZ-axis and adjusted along the Y-axis to create a distance between theblades, or other cutting member being used, sufficient to create aresultant beam of a desired thickness, then the cutting assemblies arebrought down along the Z-axis and across the stock material 202. Hence,the machine is able to produce straight cut resultant beams, likeresultant beam 520. A straight cut resultant beam 520 will enablegreater and more consistent flexibility, due to the linear shape of theresultant beam, while retaining at least the same torquability as theradius cut beam, without the increased possibility of breakage.

To adjust the relative gap distance (or the resultant beam) between theblades or cutting members, a cut can be made, the resultant beammeasured, and the cutting assemblies can be further adjusted along theY-axis until a resultant beam of the desired width has been created.Alternatively, a reference stock of a known width can be placed betweenthe blades/cutting members until both blades/members touch the referencestock.

As noted, a radius cut beam 510 or a convex cut beam 530 could becreated by the herein disclosed micro-cutting machine by moving thecutting assemblies inward and outward along the Y-axis as each cut isbeing made. It would also be possible to make a variety of other typesof cuts and resultant beams by varying combinations of elements at thesame time, such as rotating the stock material 202 with the rotationmotor as a cut is being made, or rotating the stock material 202 andmoving the cutting assemblies along the Y-axis at the same time. Forexample, a spiral cut could be made by leaving the cutting assemblies ata set Y-axis position while the stock material 202 is rotated by therotational motor. As these types of cuts have not been possible before,the advantages of the different cuts is not yet fully known, but it canalready be anticipated that a convex cut beam 530 would have even betterflexibility and torquability properties than either the straight cutbeam 520 or the radius cut beam 510.

As previously noted, the automated feedback and control process carriedout by the imaging system 400 and the processor 130 can account forslight variances in cutting blade variations or in variations orimperfections of the stock material itself. The resultant beam, asdiscussed above, is the critical dimension and could be affected by evena single blade variation (such as a single blade tooth being too long)or by a variation of the diameter of the stock material throughout itslength. All these factors are of course integrated into and manifestthemselves in the resultant beam dimension. The precise measurement andadjustment capabilities of the embodiment result in unprecedentedprecision. Upon measurement of the resultant beam, the centering of theresultant beam with respect to the located stock surfaces, and thealignment of the two cuts to each other, the processor 130 can makeadjustments to bring all parameters into alignment to create preciseresultant beam widths. This process can be executed at the beginning ofmanufacture, as a set-up process, as one or more cuts are being made, asa periodic check, or as each and every cut is being made. The softwarerun on processor 130 can be used to validate the repeatability of themicro-cutting machine, possibly reducing the number of measurementsnecessary while cutting a piece, or rendering continuous measurementsunnecessary.

The micro-cutting machine of the embodiment, as previously noted, iscapable of micro-cutting a wide variety of stock materials. Traditionalsingle-blade micro-cutting machines make use of electromagnetic sensingof the precise location of the stock material relative to the singleblade, thereby requiring the use of stock material that is conductive.This condition rules out the use of plastic tubing stock material or anyother non-conductive or minimally conductive material (referred toherein as “non-conductive” even if the material has some relatively lowconductivity that is insufficient to be cut by prior machines).

As discussed, the high definition images and measuring capabilities ofthe imaging system and the precise positioning of the cutting assembliesof the embodiment are much more accurate than relying upon sensing asurface of the stock material because the stock material itself can havean imperfect or inconsistent diameter. Therefore, the herein disclosedmicro-cutting machine is much more accurate and can therefore cut finerdimension resultant beams with greater reliability. The physicalarrangement of the components of the cutting assembly 140 and the stockmaterial 202 make it possible to cut harder materials with less naturalflexibility, like stainless steel, because the resultant beams can becut very narrow while retaining precision. The dual blade micro-cuttingmachine of the embodiment is therefore fully capable of cuttingstainless steel catheters and guidewires (greatly desired by surgeonsfor its ability to hold a shape—allowing the surgeon to personally shapethe tip of a stainless steel guidewire to match the patient'sendovascular system just prior to use), plastic catheters and guidewires(desirable for their great flexibility at relatively wider diameters),and other non-magnetic stock materials for all types of products.

Flexible yet torquable products are formed by repeating micro-cutsthroughout either the entire length of a piece of stock material, oralong one or more portions of the piece of stock material. Ideally, thepairs of cuts (a pair of cuts refers to one pass by the dual blades eventhough the cuts may not be opposite) are ideally made in a rotatingpattern along the longitudinal axis of the cylindrical stock material. Arotating pattern is preferred because making all cuts at the same anglecreates a product that is biased toward flexing in onedirection—perpendicular to the resultant beam. If the stock material isrotated about its longitudinal axis between a prior cut and a next cutor a prior pair of cuts and a next pair of cuts, then the resultantbeams are not all aligned in the same plane and the flexing bias islessened or eliminated. This rotation between cuts is facilitated byfeed motor 210 and the rotational motor, illustrated in FIG. 2. Feedmotor 210 grips the stock material 202 as the rotational motor rotatesthe stock material 202 along the X-axis (the longitudinal axis of thestock material 202), according to directions received by electroniccontrollers 110 and determined by processor 130. The rotation betweenpairs of cuts is referred to as a variance, and is measured in thedegree of rotation about the longitudinal axis of the stock material.

FIGS. 6A and 6B illustrate two examples of a rotating pattern of pairsof cuts and resultant beams. FIG. 6A illustrates a ninety degreevariance guidewire 601 that was micro-cut using the dual blademicro-cutting machine of the embodiment. Cross-sectional view 620illustrates the two different angles at which pairs of cuts are madewhen the stock material is rotated ninety degrees between cuts. Planeview 630 illustrates how such a guidewire 601 appears along its length.FIG. 6B illustrates a forty-five degree variance guidewire 602 that wasmicro-cut using the dual blade micro-cutting machine of the embodiment.Cross-sectional view 640 illustrates the four angles at which pairs ofcuts are made when the stock material is rotated forty-five degreesbetween cuts. Plane view 650 illustrates how such a guidewire 602appears along its length.

A ninety degree variance, as illustrated by guidewire 601 in FIG. 6A, issignificantly better than aligning all resultant beams in the sameplane, but is still not ideal. The ninety degree variance results inresultant beams that are perfectly perpendicular to each other, whichmay cause the overall guidewire to be biased toward flexing in twodirections—upward and downward, and to the left and to the right, if theguidewire is aligned like guidewire 601 in FIG. 6A. Using a forty-fivedegree variance between cuts, like guidewire 602 in FIG. 6B, can improvethe flexing situation, because the resultant beams are now no longeroppositely aligned in only two planes. This form of cuts evens out theguidewire's flexing properties so that it is not biased in two distinctdirections. In fact, an exemplary embodiment may utilize an unevenvariance between cuts, such as ninety-five degrees, or forty degrees, sothat the pairs of cuts, and therefore the resultant beams, truly spiralaround the longitudinal axis—completely eliminating flexing bias in anyone direction. Of course, the variance used in cutting a product can beeven more complex. For example, advantageous results can be achieved byusing a ninety degree variance between a first cut and a second cut, andthen rotating the stock material slightly, such as by five degrees,before making a third cut and a fourth cut, the third cut and the fourthcut again using a ninety degree variance.

An additional feature of the dual blade micro-cutting machine of theembodiment is an ability to cut a serial number using the blades 234 orcutting member as controlled by the cutting assembly 140, electroniccontrollers 110 and CPU 130 into the stock material 202, so that thefinal product can be individually identified. The serial number or otherform of identification could be formed by creating a series of cuts inthe stock material 202 (possibly circumferentially so they can be readregardless of the rotation of the stock material 202) of varying widthand/or varying spacing that could be read in a manner similar to a barcode.

Finally, it should be noted that while throughout the specification themicro-cutting machine has been described as utilizing a pair of cuttingblades cutting simultaneously, it also may be possible to configure amicro-cutting machine utilizing two or more pairs of cutting blades ormembers operating concurrently. In this way, it may be possible tooperate a plurality of resultant beams all at one time. In such aconfiguration, the pairs of cutting members would all be communicativelyconnected to electronic controllers 110 and processor 130, so that theycan each be adjusted in unison to machine a product meeting the desiredresultant beam parameters.

While embodiments have been illustrated and described herein, it is tobe understood that the techniques described herein can have a multitudeof additional uses and applications. Accordingly, the invention shouldnot be limited to just the particular description and various drawingfigures contained in this specification that merely illustrate one ormore embodiments and application of the principles of the invention.

What is claimed is:
 1. A micro-cutting system for forming cuts along alength of a stock material to form a product, comprising: a cuttingapparatus including a first cutting member, a second cutting member, andone or more motors operably coupled to said first cutting member andsaid second cutting member, said one or more motors configured tocontrol a relative gap distance along a Y-axis between said firstcutting member and said second cutting member and further configured tomove said first cutting member and said second cutting membersubstantially parallel to a Z-axis to form a plurality of pairs of cutsin a length of stock material, each pair of cuts leaving a resultantbeam in the stock material based on said relative gap distance; and astock material controller configured to hold the stock material and feedthe stock material along an X-axis through said cutting apparatus, saidstock material controller further configured to selectively rotate thestock material by one or more predetermined angles around the X-axisbetween the plurality of pairs of cuts to form one or more offsetsbetween the plurality of pairs of cuts.
 2. The system of claim 1,wherein at least one of said first cutting member or said second cuttingmember includes a blade having a blade thickness between about 0.002inches and about 0.008 inches.
 3. The system of claim 1, wherein theresultant beam is selected from the group consisting of a radius cutbeam, a straight cut beam, a convex cut beam, and a spiral cut beam. 4.The system of claim 1, wherein at least one of said one or morepredetermined angles is between about 5 degrees and 90 degrees.
 5. Thesystem of claim 1, wherein at least one of said one or morepredetermined angles is between about 5 degrees and about 45 degrees. 6.The system of claim 1, wherein said stock material controller includes arotational motor that selectively rotates the stock material by said oneor more predetermined angles around the X-axis.
 7. The system of claim6, wherein said rotational motor rotates the stock material atpredetermined speed around the X-axis as said first cutting blade andsaid second cutting blade simultaneously form each pair of cuts.
 8. Thesystem of claim 1, wherein said stock material controller includes atleast one feed motor configured to hold the stock material and feed thestock material forward along the X-axis a predetermined distance.
 9. Thesystem of claim 8, wherein said at least one feed motor feeds the stockmaterial forward along the X-axis at a predetermined speed.
 10. Thesystem of claim 1, further comprising an electronic controllercommunicatively coupled to said cutting apparatus and said stockmaterial controller, said electronic controller configured to controloperation of said cutting apparatus and said stock material controller.11. The system of claim 10, wherein said one or more predeterminedangles is controlled by said electronic controller.
 12. The system ofclaim 1, wherein said first cutting blade and said second cutting bladesimultaneously cut the stock material to form each pair of cuts, eachpair of cuts being on a different plane.
 13. The system of claim 1,further comprising: an imaging system collecting an image data of thestock material and the resultant beam after one or more of the pluralityof pairs of cuts are made in the stock material and transmitting saidimage data; and a processor communicatively coupled to said imagingsystem receiving the image data from the imaging system and measuring atleast an uncut diameter of the stock material and a width of theresultant beam.
 14. The system of claim 13, wherein said imaging systemincludes a camera positioned on a first side of an imaging area and oneor more light sources positioned on a first side and on an opposite sideof said imaging area, said one or more light sources illuminating thestock material and the resultant beam within said imaging area and saidcamera capturing said image data as the stock material and the resultantbeam are illuminated.
 15. The system of claim 14, wherein said one ormore light sources back-light the stock material and the resultant beamwithin said imaging area to increase visual contrast at one or moreedges of the stock material to enable a measurement of the uncutdiameter and the width.
 16. The system of claim 13, wherein said firstcutting blade and said second cutting blade simultaneously cut the stockmaterial to form each pair of cuts, wherein said imaging system capturesan image for one or more of each pair of cuts on a periodic basis or arandom basis, and said processor stores said image.
 17. A system forforming a plurality of cuts along a length of a stock material to form aproduct, comprising: a cutting apparatus including a first cutting bladeand a second cutting blade, said cutting apparatus including a firstspindle motor driving said first cutting blade and a second spindlemotor driving said second cutting blade, said cutting apparatusincluding a first stepper motor moving said first cutting blade along aY-axis and a second stepper motor moving said second cutting blade alongthe Y-axis to create a relative gap distance along the Y-axis betweensaid first cutting blade and said second cutting blade, said cuttingapparatus including a third motor moving said first cutting member andsaid second cutting member substantially parallel to a Z-axis to formeach pair of cuts among the plurality of cuts, each pair of cuts leavinga resultant beam in the stock material based on the relative gapdistance; and a stock material controller including at least a feedmotor configured to hold the stock material for a first pair of cutsamong the plurality of cuts and feeding the stock material forward alongthe X-axis a predetermined distance, and holding the stock material fora second pair of cuts among the plurality of cuts, said stock materialcontroller further including a rotational motor configured to rotate thestock material by a predetermined angle around the X-axis between thefirst pair of cuts and the second pair of cuts such that the first pairof cuts is offset from the second pair of cuts by the predeterminedangle; an electronic controller communicatively coupled to the stockmaterial controller controlling operation of the stock materialcontroller to feed the stock material along the X-axis after each pairof cuts has been formed and communicatively coupled to the cuttingapparatus controlling operation of the first motor to form each pair ofcuts and controlling operation of the first stepper motor and the secondstepper motor that control the relative gap distance.
 18. The system ofclaim 17, wherein said first spindle motor and said second spindle motorcontrol a rotational speed of said first cutting blade and said secondcutting blade.
 19. A method of cutting along a length of a stockmaterial to form a product, the method comprising: moving the stockmaterial to a first position along an X-axis; controlling a relative gapdistance along a Y-axis between a first cutting member and a secondcutting member; moving said first cutting member and said second cuttingmember along a Z-axis to cut a first pair of cuts in the stock materialleaving a first resultant beam in the stock material having a widthapproximately equal to said relative gap distance; moving the stockmaterial to a second position along the X-axis; rotating the stockmaterial by a predetermined angle around the X-axis; moving said firstcutting member and said second cutting member along the Z-axis to cut asecond pair of cuts in the stock material leaving a second resultantbeam in the stock material, wherein said first pair of cuts is offsetfrom said second pair of cuts by said predetermined angle.
 20. Themethod of claim 19, further comprising varying said relative gapdistance between said first pair of cuts and said second pair of cuts.